Well this is one of the repairs that takes a little bit of setup but isn't all that hard to do. Roasted maple tends to be very brittle. If you don't make your holes a little larger you risk blowing out like this. Here I take my cnc router rails and clean up the hole.
first I glue it up.
then I route a new spline in.
then I do that on the other side as well.
I scrape and sand it and its all ready for finish.